ObjectivesAn investigation of the effects of different types of the inferior mesenteric artery (IMA) on laparoscopic left colic artery (LCA) radical resection of rectal cancer was conducted.MethodsClinical data were collected from 92 patients who underwent laparoscopic radical resection of rectal cancer with preservation of the LCA at Nantong University’s Second Affiliated Hospital. All patients underwent full-abdominal dual-energy CT enhancement examination before surgery and 3D post-processing reconstruction of the IMA. Two radiologists with >3 years of experience in abdominal radiology jointly conducted the examination. A total of three types of IMA were identified among the patients: IMA type I (the LCA arising independently from the IMA), type II (LCA and sigmoid colon artery [SA] branching from a common trunk from IMA), and type III (LCA, SA, and superior rectal artery [SRA] branching from the IMA at the same point). The baseline data, pathological results, and intra-operative and post-operative indicators of the groups were analyzed.ResultsThe proportions of type I, type II, and type III IMA were 58.70% (54/92), 18.48% (17/92), and 22.82% (21/92), respectively. IMA typing was consistent with the preoperative CT evaluation results. The intra-operative blood loss of type III IMA patients [median (interquartile spacing), M (P25, P75): 52.00 (39.50, 68.50) ml] was higher than that of type I and II IMA patients [35.00 (24.00, 42.00) and 32.00 (25.50, 39.50) ml, respectively] (P<0.05). The incidence of anastomotic fistula in type III IMA patients (4 cases, 19.05%) was higher than that in non-type III IMA patients (1 case, 1.41%) (X2=6.679, P=0.010). The incidence of postoperative complications among the three types of IMA was not significantly different (P>0.05).ConclusionsAmong rectal cancer patients undergoing laparoscopic LCA preservation, type III IMA patients had more intraoperative bleeding and a higher incidence of postoperative anastomotic fistula. However, this did not increase the risk of overall postoperative complications.